Jupiter—A Waiting Giant

On the Cover: Jupiter, with its Great Red Spot (lower left), and its retinue of Galilean satellites—lo (center), Europa (far right), Ganymede (not pictured) and Callisto (bottom left)—were last visited by spacecraft from Earth in 1979, when Voyagers 1 and 2 flew through the system. They were to be shortly followed by Galileo, an ambitious orbiter and atmospheric probe mission once scheduled for launch in late 1981 or early 1982 from the space shuttle. Problems with the shuttle have repeatedly delayed Galileo's launch, and it is now scheduled to be on its way in October of this year, to arrive at Jupiter in 1996.JPL / NASA

Features

4 The Solar System in Chaos: Eugene Mallove shows that the orbits of bodies in the solar system don't exactly behave like clockwork.

8 A Triumphant Beginning: Bruce Murrayexplains the delay of the launch of Galileo.

14 The Phobos Argosy—A Brave and Bitter Tale: James Burkediscusses the failure of the USSR's two Phobos spacecraft.